... | ... | @@ -11,7 +11,7 @@ For detailed wave equations look at [this section](https://git-xen.lmgc.univ-mon |
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![fig1](uploads/2b484fd324a478d488f2d7d464111065/fig1.png)
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While constructing the optical system with a pair of crossed polarizers, it is extremely crucial to have them aligned the exact same way as illustrated in the image above in order to obtain the correct photo-elastic response from the stressed material. There are two ways to obtain circular polarizers: (1) purchase linear polarizers and quarter-wave plates and align the polarization axes and fast axes as shown in the figure above; (2) purchase circular polarizers, which are pre-aligned linear polarizer with quarter-wave plate combined together, and make sure light passes these two polarizers in the correct order. For the second method, due to two sides of the circular polarizer being indistinguishable, it is common to accidentally flip one or two of the circular polarizers, which will result in wrong polarized image for analysis. The following figure shows examples of photo-elastic response from correct and wrong polarizer arrangement in the second method.
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While constructing the optical system with a pair of crossed polarizers, it is extremely crucial to have them aligned the exact same way as illustrated in the image above in order to obtain the correct photo-elastic response from the stressed material. There are two ways to obtain circular polarizers: (1) purchase linear polarizers and quarter-wave plates and align the polarization axes and fast axes as shown in the figure above; (2) purchase circular polarizers, which are pre-aligned linear polarizer with quarter-wave plate combined together, and make sure light passes these two polarizers in the correct order. For the second method, due to two sides of the circular polarizer being almost indistinguishable, it is common to accidentally flip one or two of the circular polarizers, which will result in wrong polarized image for analysis. A nice and easy way to figure out linear polarizer side and quarter-wave plate side can be referred to [this session](). The following figure shows examples of photo-elastic response from correct and wrong polarizer arrangement in the second method.
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